package cn.njupt.set;

public interface Set<E>{

    public abstract int size();
    public abstract boolean isEmpty();
    public abstract void clear();
    public abstract boolean contains(E element);
    public abstract void add(E element);
    public abstract void remove(E element);
    public abstract void traversal(Visitor<E> visitor);


    public abstract class Visitor<E>{
        boolean stop;
        public abstract boolean visit(E element);
    }


}
